Light modulating device

Abstract

A light modulating device is disclosed herein. In some embodiments, a light modulating device includes a first substrate, a second substrate, a light modulation layer, and a retardation film, wherein each of the first and second substrates has a first surface and a second surface, wherein the first and second surfaces are disposed opposite to each other, wherein the first surfaces of the first and second substrates face each other, wherein the light modulation layer is disposed between the first and second substrates, wherein the retardation film is formed on the second surface of the first substrate or the second substrate, and wherein the retardation film has an in-plane phase difference in a range of 100 nm to 300 nm for light having a wavelength of 550 nm. The light modulating device can be control omnidirectional light leakage in a black mode while having excellent optical properties and mechanical properties.

The invention claimed is: 
     
       1. A light modulating device, comprising:
 a first substrate; 
 a second substrate; 
 a light modulation layer; 
 an optically anisotropic layer; 
 a first polarization layer; 
 a second polarization layer; and 
 a retardation film, 
 wherein each of the first and second substrates has a first surface and a second surface, wherein the first and second surfaces are disposed opposite to each other, 
 wherein the first surfaces of the first and second substrates face each other, 
 wherein the first and second substrates are each anisotropic substrates having an in-plane phase difference of 500 nm or more for light with a wavelength of 550 nm, 
 wherein the light modulation layer is disposed between the first and second substrates; 
 wherein the retardation film is formed on the second surface of the first substrate or the second substrate, 
 wherein the first polarization layer is formed on the second surface of the first substrate or on the retardation film, 
 wherein the second polarization layer is formed on the second surface of the second substrate or on the retardation film, 
 wherein the retardation film has an in-plane phase difference in a range of 100 nm to 300 nm for light having a wavelength of 550 nm, 
 wherein the retardation film is disposed such that the slow axis of the retardation film and the slow axes of the anisotropic substrates are perpendicular or horizontal to each other, 
 wherein the optically anisotropic layer is disposed between at least one of the light modulation layer and the first substrate or between the light modulation layer and the second substrate, wherein the optically anisotropic layer satisfies Equation 3 below:
     nz<ny≈nx   [Equation 3]
 
 
 wherein, nx is the refractive index of the optically anisotropic layer for light with a wavelength of 550 nm in the slow axis direction, ny is the refractive index of the optically anisotropic layer for light with a wavelength of 550 nm in the fast axis direction, and nz is the refractive index of the optically anisotropic layer in the thickness direction, and 
 wherein the slow axis of the retardation film and the absorption axis of the first or second polarization layer that is adjacent to the retardation film are perpendicular to each other. 
 
     
     
       2. The light modulating device according to  claim 1 , wherein the retardation film satisfies the following Equation 1 or Equation 2:
     nx>ny≈nz   [Equation 1]
 
     nx≈nz>ny   [Equation 2]
 
 wherein, nx is the refractive index of the retardation film for light with a wavelength of 550 nm in the slow axis direction, ny is the refractive index of the retardation film for light with a wavelength of 550 nm in the fast axis direction, and nz is the refractive index of the retardation film in the thickness direction. 
 
     
     
       3. The light modulating device according to  claim 1 , further comprising:
 an adhesive layer or a pressure-sensitive adhesive layer is formed on the first surface of the first substrate; and 
 a liquid crystal alignment film is formed on the first surface of the second substrate. 
 
     
     
       4. The light modulating device according to  claim 3 , wherein the adhesive layer or the pressure-sensitive adhesive layer is a silicone adhesive layer or a silicone pressure-sensitive adhesive layer. 
     
     
       5. The light modulating device according to  claim 3 , wherein no liquid crystal alignment film is formed on the first substrate. 
     
     
       6. The light modulating device according to  claim 3 , wherein the liquid crystal alignment film is a vertical alignment film. 
     
     
       7. The light modulating device according to  claim 1 , wherein absorption axes of the first and second polarization layers are perpendicular to each other. 
     
     
       8. The light modulating device according to  claim 1 , wherein the slow axes of the first and second substrates are horizontal to each other. 
     
     
       9. The light modulating device according to  claim 3 , wherein the orientation direction of the liquid crystal alignment film and the slow axes of the first and second substrates are horizontal or perpendicular to each other. 
     
     
       10. The light modulating device according to  claim 1 , further comprising a partition wall-shaped spacer to maintain a distance between the first and second substrates. 
     
     
       11. The light modulating device according to  claim 1 , wherein the light modulation layer comprises a liquid crystal compound. 
     
     
       12. The light modulating device according to  claim 1 , wherein the light modulation layer capable of switching between a vertical orientation mode and a horizontally twisted mode. 
     
     
       13. The light modulating device according to  claim 12 , wherein a ratio of the thickness d of the light modulation layer to the pitch p of the twisted mode is 1 or less. 
     
     
       14. A window comprising the light modulating device of  claim 1 . 
     
     
       15. A sunroof comprising the light modulating device of  claim 1 .